Horn for fire extinguisher

Abstract

The invention provides a fire extinguisher horn having an inner tube, through which gas may pass from the nozzle of the fire extinguisher to the atmosphere, and an outer tube surrounding the inner tube to form a chamber around the inner tube along at least part of its length. The chamber provides an insulating space between the inner and outer tubes so that, although the inner tube may become very cold in use as the extinguisher gas expands through it, the outer surface of the outer tube remains closer to the ambient temperature. Thus, it is possible to hold the extinguisher horn safely. Preferably, the horn further comprises apertures that allow atmospheric air to flow through the chamber when the extinguisher is in use, maintaining the temperature of the chamber and, hence, of the outer tube close to the ambient air temperature.

1 . A fire extinguisher horn, comprising: means for attaching the horn to the nozzle of a fire extinguisher; an inner tube, through which gas may pass downstream from the nozzle of the fire extinguisher to the atmosphere; and an outer tube surrounding the inner tube and spaced therefrom to form a chamber around the inner tube along at least part of its length.  
     
     
         2 . A fire extinguisher horn, comprising:means for attaching the horn to the nozzle of a fire extinguisher; an inner tube, through which gas may pass downstream from the nozzle of the fire extinguisher to the atmosphere; and an outer tube surrounding the inner tube and spaced therefrom to form a chamber around the inner tube along at least part of its length, at least one upstream aperture that allows air to flow from the atmosphere into the upstream end of the chamber closer to the nozzle attachment; and at least one downstream aperture that allows air to flow from the downstream end of the chamber into the atmosphere.  
     
     
         3 . A fire extinguisher horn according to  claim 3 , comprising a plurality of the downstream apertures spaced around the circumference of the horn.  
     
     
         4 . A fire extinguisher horn according to any preceding claim, wherein a flange extends outwards from the downstream end of the inner tube to form a downstream end wall of the chamber.  
     
     
         5 . A fire extinguisher horn according to  claim 4 , wherein the outer tube is formed separately from the inner tube; and wherein the tube has at least one inward projection, which engages the flange of the inner tube to retain the outer tube in position around the inner tube.  
     
     
         6 . A fire extinguisher horn according to any preceding claim, wherein the means for attachment to the nozzle of a fire extinguisher is integral with the inner tube.  
     
     
         7 . A fire extinguisher horn according to any preceding claim, wherein each of the inner and outer tubes has a generally frustoconical shape, the inner and outer tubes being concentric.